Most common ways to preserve food
Besides using chemical substances to preserve food, there are other, more common, ways that most people use today. Drying is one of the oldest methods to preserve food and it deals with removing the moisture from the food in order to kill any micro-organisms. Refrigeration is the most common food preservation method. Putting food in the refrigerator's cold environment can help slow down enzyme growth and micro-bacterial reproduction. Another method that is similar to refrigerators is freezing. Freezers are a common household appliance, but only certain foods need to be in the extremely cold environment of the freezer. Vacuum packing is a method in which the food is kept and an air-tight compartment. This enclosed environment deprives the micro-organisms of needed oxygen, thus killing them. A common way of vacuum packing is the use of zip-lock bags. Another way to remove moisture from the food is to use salting. Nitrates and nitrites are often times put on meat, which cause meat to retain its pink color. Sugar is used similarly to salt, but sugar is usually used on fruits. This sugar can either be in its crystallized form, or it can be made into a syrup substance to pour on top of the food. A large number of synthetically produced food additives exist, each type with its own purpose. For example, antimicrobial additives inhibit the growth of bacteria or other micro-organisms.